Abstract
We study the leptoquark model of Buchmüller, Rückl and Wyler, focusing on a particular type of scalar (R2) and vector (U1) leptoquark. The primary aim is to perform the calculations for leptoquark production and decay at next-to-leading order (NLO) to establish the importance of the NLO contributions and, in particular, to determine how effective the narrow-width-approximation (NWA) is at NLO. For both the scalar and vector leptoquarks it is found that the NLO contributions are large, with the larger corrections occurring for the case vector leptoquarks. For the scalar leptoquark it is found that the NWA provides a good approximation for determining the resonant peak, however the NWA is not as effective for the vector leptoquark. For both the scalar and vector leptoquarks there are large contributions away from the resonant peak, which are missing from the NWA results, and these make a significant difference to the total cross-section.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
W. Buchmüller, R. Ruckl and D. Wyler, Leptoquarks in Lepton-Quark Collisions, Phys. Lett. B 191 (1987) 442 [Erratum ibid. B 448 (1999) 320] [INSPIRE].
ATLAS collaboration, Search for first generation scalar leptoquarks in pp collisions at \( \sqrt{s}=7 \) TeV with the ATLAS detector, Phys. Lett. B 709 (2012) 158[Erratum ibid. B 711 (2012)442] [arXiv:1112.4828] [INSPIRE].
ATLAS collaboration, Search for second generation scalar leptoquarks in pp collisions at \( \sqrt{s}=7 \) TeV with the ATLAS detector, Eur. Phys. J. C 72 (2012) 2151[arXiv:1203.3172] [INSPIRE].
ATLAS collaboration, Search for third generation scalar leptoquarks in pp collisions at \( \sqrt{s}=7 \) TeV with the ATLAS detector, JHEP 06 (2013) 033[arXiv:1303.0526] [INSPIRE].
CMS collaboration, Search for pair production of first- and second-generation scalar leptoquarks in pp collisions at \( \sqrt{s}=7 \) TeV, Phys. Rev. D 86 (2012) 052013 [arXiv:1207.5406] [INSPIRE].
CMS collaboration, Search for Pair-production of Second generation Leptoquarks in 8 TeV proton-proton collisions, CMS-PAS-EXO-12-042 (2013).
CMS collaboration, Search for pair production of third-generation scalar leptoquarks and top squarks in proton-proton collisions at \( \sqrt{s}=8 \) TeV, Phys. Lett. B 739 (2014) 229 [arXiv:1408.0806] [INSPIRE].
A. Belyaev, C. Leroy, R. Mehdiyev and A. Pukhov, Leptoquark single and pair production at LHC with CalcHEP/CompHEP in the complete model, JHEP 09 (2005) 005 [hep-ph/0502067] [INSPIRE].
I. Dorsner, S. Fajfer and A. Greljo, Cornering Scalar Leptoquarks at LHC, JHEP 10 (2014) 154 [arXiv:1406.4831] [INSPIRE].
T. Mandal, S. Mitra and S. Seth, Single Productions of Colored Particles at the LHC: An Example with Scalar Leptoquarks, JHEP 07 (2015) 028 [arXiv:1503.04689] [INSPIRE].
M. Krämer, T. Plehn, M. Spira and P.M. Zerwas, Pair production of scalar leptoquarks at the CERN LHC, Phys. Rev. D 71 (2005) 057503 [hep-ph/0411038] [INSPIRE].
M. Krämer, T. Plehn, M. Spira and P.M. Zerwas, Pair production of scalar leptoquarks at the Tevatron, Phys. Rev. Lett. 79 (1997) 341 [hep-ph/9704322] [INSPIRE].
N. Kauer, A threshold-improved narrow-width approximation for BSM physics, JHEP 04 (2008) 055 [arXiv:0708.1161] [INSPIRE].
N. Kauer, Narrow-width approximation limitations, Phys. Lett. B 649 (2007) 413 [hep-ph/0703077] [INSPIRE].
D. Berdine, N. Kauer and D. Rainwater, Breakdown of the Narrow Width Approximation for New Physics, Phys. Rev. Lett. 99 (2007) 111601 [hep-ph/0703058] [INSPIRE].
P. Mastrolia, G. Ossola, T. Reiter and F. Tramontano, Scattering AMplitudes from Unitarity-based Reduction Algorithm at the Integrand-level, JHEP 08 (2010) 080 [arXiv:1006.0710] [INSPIRE].
S. Catani and M.H. Seymour, A general algorithm for calculating jet cross-sections in NLO QCD, Nucl. Phys. B 485 (1997) 291 [Erratum ibid. B 510 (1998) 503] [hep-ph/9605323] [INSPIRE].
S. Catani, S. Dittmaier, M.H. Seymour and Z. Trócsányi, The dipole formalism for next-to-leading order QCD calculations with massive partons, Nucl. Phys. B 627 (2002) 189 [hep-ph/0201036] [INSPIRE].
T. Plehn, H. Spiesberger, M. Spira and P.M. Zerwas, Formation and decay of scalar leptoquarks/squarks in e p collisions, Z. Phys. C 74 (1997) 611 [hep-ph/9703433] [INSPIRE].
A. Alves, O. Eboli and T. Plehn, Stop lepton associated production at hadron colliders, Phys. Lett. B 558 (2003) 165 [hep-ph/0211441] [INSPIRE].
Open Access
This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited.
Author information
Authors and Affiliations
Corresponding author
Additional information
ArXiv ePrint: 1501.06719
Rights and permissions
Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0), which permits use, duplication, adaptation, distribution, and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
About this article
Cite this article
Hammett, J., Ross, D. NLO leptoquark production and decay: the narrow-width approximation and beyond. J. High Energ. Phys. 2015, 148 (2015). https://doi.org/10.1007/JHEP07(2015)148
Received:
Revised:
Accepted:
Published:
DOI: https://doi.org/10.1007/JHEP07(2015)148